FIG. 9 illustrates an example of an existing electromotive unit incorporated into an electric shaver disclosed in Japanese Patent Unexamined Publication No. 2007-89709.
Electromotive unit 100 includes linear motor 110, case 120 containing linear motor 110, movable element 130 joined to linear motor 110, and sealing material 140 made of rubber sealing the gap between movable element 130 and the opening of case 120.
Sealing material 140 is formed between movable element 130 and the opening of case 120, and has projection 141 projecting outside case 120. When movable element 130 is reciprocatingly driven with respect to case 120, projection 141 is elastically deformed. This causes movable element 130 to be reciprocatingly driven with respect to case 120 and the gap between movable element 130 and the opening of case 120 to be sealed.